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De-Carb Question

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Old Oct 10, 2005 | 11:07 PM
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Default De-Carb Question

I was considering doing a de-carbonization using the top engine cleaner from GM. I was planning on following the procedure I have heard many times on the forum: open the pcv valve, pour two cans of top engine cleaner in while the car is running at idle, let it sit over night, then do an oil change. I dont have any knocking or pinging (car has 38K miles).

I spoke with a GM tech who mentioned that this is not a safe way to do the decarb and it probably isnt even necessary. He said the proper way would be to remove the spark plugs, pour in the engine cleaner that way, and manually turn the engine over.

Are these procedures correct? Should the decarb really be done with the engine running? How do you know if you actually need to do a decarb? thanks in advance

Last edited by Icemanskis; Oct 10, 2005 at 11:11 PM.
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Old Oct 10, 2005 | 11:11 PM
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Yes the engine has to be running. If you have alot of miles it may need to be done. But the engine has to be running in order to burn the carbon out, if not you can water lock the engine.
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Old Oct 11, 2005 | 02:39 AM
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Originally Posted by Icemanskis
I was considering doing a de-carbonization using the top engine cleaner from GM. I was planning on following the procedure I have heard many times on the forum: open the pcv valve, pour two cans of top engine cleaner in while the car is running at idle, let it sit over night, then do an oil change. I dont have any knocking or pinging (car has 38K miles).

I spoke with a GM tech who mentioned that this is not a safe way to do the decarb and it probably isnt even necessary. He said the proper way would be to remove the spark plugs, pour in the engine cleaner that way, and manually turn the engine over.

Are these procedures correct? Should the decarb really be done with the engine running? How do you know if you actually need to do a decarb? thanks in advance
One step you missed. That is after letting the car set 12 hours start it up and all this black smoke will come out the tail pipes. Run it on the hwy or in the driveway until all smoke is clear. Then change oil, filter and spark plugs. BUT you maynot need to do a de-carb. You can get by using Chevron Thecron fuel treatment.
Good luck..
Rsty
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Old Oct 11, 2005 | 03:08 AM
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We did it on a couple of cars, years ago. Tech ran some in while running, then removed all spark plugs. He poured a little in each cylinder and let it sit overnight. In the morning, he installed new spark plugs and fired it up. You could hear the carbon rattling out for a few moments. Fixed detonation problem.

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Old Oct 11, 2005 | 08:57 AM
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Default I'm no expert..BUT

I do know...
If it ain't broke...Don't fix it!!

Don't ask me how I know this!
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Old Oct 11, 2005 | 09:10 AM
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I don't know...some of these 'pour some in the spark plug holes' recommendations sounds like trouble. Pour a little too much in one of the cylinders, BAM, there go the rings. I'm not sure how 'metered' the PCV method is, but that sounds like it would be the safer way, assuming it's not sucking in the entire bottle in a short time.

I'm with the PCV guys. I haven't done it yet on my car, but I will at some point.
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Old Oct 11, 2005 | 08:53 PM
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in the spark plug is recomended because you cannot hydrolock the engine if the plugs are out. remember instruction are often written to make sure nothing stupid happens. obviously if you dump a ton in there is the chance of hydolocking the engine when it is running. use some common sense. plain water also works wonder on the intake valves. the top cleaner does a nice job on rings/pison crowns
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Old Oct 11, 2005 | 11:24 PM
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Originally Posted by Groucho
I do know...
If it ain't broke...Don't fix it!!

Don't ask me how I know this!



If you aren't having any problems.....DON'T FIX IT!
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Old Oct 12, 2005 | 12:12 AM
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thanks for the info guys. i think i better leave well enough alone.
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Old Oct 12, 2005 | 12:11 PM
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Originally Posted by Icemanskis
thanks for the info guys. i think i better leave well enough alone.
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